Mongoose Footprints

A mongoose plugin to log changes in MongoDB documents made using mongoose methods. If used on Mongoose models, any changes made to that model will be logged as a document of the _Footprint model. It will contain an array that shows every change made to the document, along with the old and new document bodies.

Changes in referenced/populated documents will not be logged unless the referenced Object ID changes entirely to a different one. However changes in nested documents or subdocuments will be logged.

The plugin also supports sessions so queries in aborted transactions won't be logged.

Currently it supports the following operations:

• Update
  • findOneAndUpdate
  • findByIdAndUpdate
  • document.save
• Create
  • create
  • document.save
• Delete
  • findOneAndDelete
  • findByIdAndDelete
  • findOneAndRemove
  • findByIdAndRemove

Note: The update operations will set new: true as the default so the returned object will always be the updated object.

Get Started

Install the package

npm i mongoose-footprints

Then, just use the plugin on the schema before you make a model from it.

Book.js

const footprints = require('mongoose-footprints');
const mongoose = require('mongoose');

const bookSchema = mongoose.Schema({
  name: String,
  author: String,
});

const options = {
  operations: ['update', 'delete'],
  logUser: false,
};

bookSchema.plugin(footprints.plugin, options);

const Book = mongoose.model('Book', bookSchema);

Possible plugin options you can pass are given below. They are passed inside an object.

Plugin Options

• logUser: true / false - To log the user who updated the document. If set to false, the default user logged is System. If set to true, the user has to be passed in the options of the query. Otherwise, it will be recorded as Unknown. Default is false.
• operations : ['update', 'create', 'delete'] - The operations that will be logged. Default is ['update'].
• storeDocuments: true/false - Store the entire old document and updated document inside the footprint along with the list of changes. Set it to false if it causes you to exceed the maximum document size of MongoDB. Default is true.

You can pass in extra options during mongoose queries that are specific to that operation.

Query Options

• footprint: true / false - Set it to false to not create a footprint of this query. Default is true.
• user: mongoose.Schema.Types.Mixed - Can be any data type. This will log the user who made this change. Default is System if logUser is set to false, otherwise it is simply Unknown.

Example Usage

findOneAndUpdate()

await Book.findOneAndUpdate(filter, updates, {
  user: req.user,
  session: session,
});

create()

const bookObject = {
  name: 'Angels & Demons',
  author: 'Dan Brown',
};

// to use Model.create() with options, the document has to be passed in an array
// see https://mongoosejs.com/docs/api/model.html#model_Model-create
const doc = (
  await Book.create([bookObject], {
    footprint: false, // setting to false will not log this creation
  })
)[0];

save() when updating

let savedBook = await Book.findById(doc._id);
savedBook.name = 'The Da Vinci Code';
await savedBook.save({
  footprint: true, // already true by default though
});

save() when creating

const book = new Book({ name: 'Angels & Demons', author: 'Dan Brown' });
await book.save({ user: req.user });

findOneAndDelete()

await Book.findOneAndDelete(filter, {
  session: session,
});

Finder Methods

There are also some utility methods that can be used to query for footprints. The parameters are similar to that of the find() method of mongoose:

• getFootprints(filter, projection, options, callback)
• getCreations(filter, projection, options, callback)
• getDeletions(filter, projection, options, callback)
• getUpdates(filter, projection, options, callback)

Example Usage

const footprints = require('mongoose-footprints');

await footprint.getFootprints({ documentId: doc._id });

Footprint Model

{
  modelName: String,
  documentId: mongoose.Schema.Types.ObjectId,
  oldDocument: {},
  newDocument: {},
  user: mongoose.Schema.Types.Mixed,
  changes: [String],
  typeOfChange: {
    type: String,
    enum: ['Create', 'Update', 'Delete'],
    default: 'Update',
  }
}

Future Plans

• Not satisfied with how changes in arrays are documented. I have plans to make the logging much more extensive for this kind of data type.
• Test cases don't cover all sorts of scenarios at the moment, so I'll need to think of more. Currently only the core features are covered.